Safety device for gas or vapor pumps



A. MARSHALL. SAFETY DEVICE FOR G-AS ORVAFOR PUMPS.

APPLICATION FILED MAIL23| |920.'v f

f1,41.11,054f Patented Ma1-..28,1'922.

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r ALI V A.T.`MARSHALL,

SAFETY DEVICE FOR GAS 0R VAPOR PUMPS.

APPLICATION EILED'MAR 23, 1'920.

" *ALBERTHIX MBSHAILLL oniirAnTii "f "NEW qERsnY; l

.AyConnecticiitg*have invented certain new and iiset'ul-liiiprovenieiits.iii Safety lilevices for y' (llas;'ordVapoi-Pumps` of `which the vt'ollow-` ing-is a speciiicatioii.`

This invention relates to safety as those iisedin refrigeratinp' systems' in which the lcompressors exhaustfrom the re-` i'rigeratini;Y coils the yvapor which vt'o'rms during the refrigerating' process from the Huid contained in saidv coils, ln retrigerating systems. it'not infreqi'iently happens thata vlly shin' ofthe. unvaporized fluid isv draii'iivinto the pump cylinderand in some cases canses the c vliiidci" heads to be .knocked out. 'In vlow speed compressors. the danger is not as jgreat as inv high speed;machines which are vlikelvo do vconsiderable damage and eveny -cause loss "of life before theiv can be shut -"do'wnIk f "Tlie present invention hast'or its primar)v object to provide-an improved safety device. i which automatically controls the operation ot" the compressor so as to avoid serions 30 trouble whenever a slug ot' liquid reaches the. vcompressor. In the presentembodiment of iiihv invent-ion in which an electric motor is connected up/witli the coiiipi'essor anddrives it--atliigli speeih the first safety head to be lifted by the liquid slug'. is arranged to operate a switch which interrupts the motor einergizinpl circuit. Preferably, one of these devices should be placed on eacli cylinder with the trip switch connected up in series with the higlipressure cut ont and electric overload cut' out so vthat said trip switch need carry but ay very small current instead of avery much larger current which it would be necessary to control were alarger trip switch connected up in the main electric supply to the motor, jectsof invention willappear inthe specifcation and be pointedoiit in the claims. 'Iii the drawings, which represent a preferred 5'0 embodiment of my invention.

f Figure 1 is a side elevationof the tripswitch andv 'operating connections, parts 'of the compressor being1 shown in section; Figure 2 is a top plan (View m2 theiimp4 switch;

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` vdeViiies for 10.. zgas or vapor pnnips 'and more particularlQi. to high speed compressorssuch i'or example Specific. ob-

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GaisA "on vsr'onfeuiifysu ySpecificationofilietters lzitent.` v"Patgigd {i-f; 1922, i Appiicaiioiiffiied Maren 2a, 1920. -seriai imT iiisiiiiis'if f Figure is a'ragmentary sidelel'evation of they saine', parte"be`'n,gir shown insection':

Figure 4 isaw-v vingdiagra Inv-.iy. V, i f

Referring more particularly tothe-drawings', in Figure 4 is shown awiring diagram ,in'which aV positive inaiilfisconnected by a wire 2 to one endof a;`solenoidj 3,]the other end ot'l said solenoidfbeing connectedby a wiredto the: negative main'., Y Said wire 2 includes fuses 6, compressor trip switches 7, current overload ytrip switches 8 and ahigh pressure cut- .ont switch 9; lieciprei'able within the solenoid 8 is a p'liiilig'er 10 'hich carries an insulated yContact bridge 11 hicir is adapted to complete the mainjteedlme 12 ot' a motorf13 which drives the 'piston ,oi the compressor which is now to be described. Referringr to Figure "l,V the motor 13 is connected tothe compressor byl means which iri,

clude a piston rod 14, said pistonirod being connected toa piston 15 which reciprocates iii a cylinder 16 having anl extension 17. at its'upper end closed by a {ixedhead 18. The cylindrical wall of said cylinder 16 is pro vided with an inlet port: 1S)k which is connected `upto the exhaust' end' ot' a refrigerating coil (not shown). ,Closing the upper end of the piston chamber` is a lvieldable head or wall QOwhich is/ordinariljv1 retained in closed position with respect to the piston chamber by lmeans o't'afsiiriiigr'lil which is interposed between the vieldable wall Q0 and the fixed c vlinder head 18. iiccording to the present embodiment of my invention, the `vieldable Wall Q0 is' provided with a central valve opening which is closed b v a valve 2Q' yreciprocably mounted in a. cylindrical extension 20 of the yieldable wall. Said cylindrical extension Q0 is provided with a re movable' cap 23 between which and the valve 22 is interposed a compression spring '24 which yields to permit the valve 22 to open 'under predetermined conditions to admit the. compressed `gas' or vapor by means of ports 25 to the channels 26 which preferably lead to the condenser' (not shown). As has been indicated above, thel spring 21 is constructed of such strength as to normally retain the iva-11, QOinclosed position. Should, however, a- S'lug of liquid, ji. e. gas or vapor in' its liquid clondition, be drawn into the piston chamber,.the .'yieldable wall QO'Uwill he displaced upwardly the nap 23 being adapted to transmit this inoveniei'it to a plunger Q7 -whioh passes through n, stelling box 28 and has its upper end abutting against one arm of a .trip lever 29 vwhich is pivot-ally mounted on a stud 30 and has its other arm provided with .a hook 31 which normally .enga es a 'pin 32 which projects laterallyv from a and grip v33 carried by the outer end of a leaf spring 34 which is mounted uponan oscillator block 35 which carries a spring switch l 36. he. blade ofthe spring switch 36-diverges from the leai`-spring 34 and is provided with a contact-.3T which cooperates with. a-lower contact 38 when said contacts l are."together. The block 35 and spring `switch-36 is pivotally mounted on a post 39 a spring-l0 (see Figure 2) being mounted on the post 39 and .operating to throw-the switch'36 4 into -open position whenever said switch is released by the hook* 31.' The' lower contact- 38 is .carried by another post 41. both of the posts 39 and 41 being Amounted -in a slate panel 42. Connected tothe inner ends of theposts 39 and 41 are sec-v tions 2--2 of the wire 2 shown'in Figure 4.' Mounted in the slate panel 42 abovel the leaf spring 34 is a stop in 43 which prevents overthrow of the swi ch. my improved safety device. will now be 4readily understood and 'briefly described is as follows."

Normally, the. plate or Awall 2() retains the posit-ion shown in Figure 1. lhenever aslug of liquid is drawn into the piston' chamber, said plate vor wall is forced upwardly,

compressing spring 21,' raising plunger 2T,

oscillating trip 29 and releasing the switch The. motor is thereby sto )pcd by havmovable 4wall adapted to bev operated by an abnormal pressure otl the medium in lsaid pumping chamber, of a' pumping element movable in said pumplng chamber,y means- The operation ofv said movable element, and means operate by said movable wall of the chamber for controlling the operation of said movable element driving means.

3; The combinationwith a compressor comprising a cylinder provided with a yieldable wall portion adapted to be displaced b v an abnormal pressure. and a pistonrecipro'- cable in said cylinder, of means for driving said piston,'and an electric circuit 'including a swit'ch operated by said tion of the cylinder. v

4. The combination with a. cylinder provided with a yieldable wall portion, a piston reciprocable .in said cylinder, a motor for driving said piston. an electric circuit including. aA switch for controlling the-operation of said motor, Vand means operated by said yieldable wall portion for moving said switch.' 5. The combination with a cylinder having a piston chamber provided with a movable wall, a piston reciprocablein said piston chamber, mean's for driving saidpiston', an

electric circuit- .for controlling the operation ot' said piston driving means, said electric circuit being provided with a switch, and. a plunger operated .b v said movable wall and controlling the movement of said switch.

G.- ln a compressor, a piston chamber provided with a movable wall, a piston movable in said chamber', means for driving said compressor, and means operated by said movable wall for controlling the operation of said compressor driving means.

. ALBERT T. MARSHALL.

yieldable wall por- 

